Mains Gas

[Ian]

If you have mains gas it is very unlikely that a large area will be deliberately cut off because of shortages or loss of electricity.

Recent experience http://www.bbc.co.uk/news/uk-england-me ... e-15696187 is typical.

If the gas supply is cut, EVERY house has to be visited and isolated, the supply restored and then EVERY house revisited to reconnect, a massive effort that as you can see takes days. Until every house is isolated the supply will not be restored and with people out at work, on holiday etc. it takes days.

If there is a shortage, and we came to within a half hour of such action at the beginning of this year, the gas suppliers shut down the large consumers, factories and industry for example, more or less instantly. It is part of the supply contract that they may do so. They are easy to turn off and on again but, of course, it shuts down the factory until then.

The gas suppliers are extremely adverse to cutting off large areas of domestic supply and will avoid such action at all costs, what ever the reason.

To keep the gas flowing the gas suppliers have standby generators so a few days without electricity will not cost them millions and many pumping stations are on priority supplies so they probably won't get cut off deliberately in the first place.

For us on this site it means that the gas supply may be considered almost uninterruptable (Never say never) but can you use it? can you light your cooker? mine is automaticly lit by mains electricity but it will light with a match or a sparker if there is no power. Will your central heating run? probably not. I have fitted our combi gas boiler with a plug and socket instead of the normal fused spur so I may plug it into an alternative supply, generator, UPS or in my case our Prius via an inverter, works well.

Have a think about the problem before you need it in earnest. It must be annoying to be cold and have no hot water just because you cannot access the available gas supply.

[Brambles]

I never knew it was that complicated to shut off an area, I just assumed they would be able to switch off at a pumping station, so to speak.
I gave this some thought a while ago too. I have mains Gas, it runs my central heating and hot water. I know I would have no central heating (electric pump) but I presume I would sill have hot water because the pilot light on the boiler stays on. I'd like a gas cooker, but there's no pipework for one.

[the-gnole]

Hi Ian,

Good post, We got a cooker which can be altered to run on LPG in about an hour and we are looking at getting an extra gas fire insert that uses LPG as well, only the boiler would suffer loss if we lost mains gas for an extended period, if a day or two we have alternate methods of doing things.

I remember the change over from "Town gas" to what they called back then "North sea gas", all the flare off points going to burn off the old and await the new.

It was a major undertaking at the time, today it would be even bigger as so many more are linked to the system.

I am a gas engineer and when we do the bigger above ground lines it is a long process as the old lines need to be purged of gas and replaced with Nitrogen, then the gas purge needs to be calculated so that a 95% gas level is achieved within a set time, or it is purged again. can be a long day getting it right.

A factory up the road used to use 1.5 million cubic feet of gas a day, if they cut its supply they had back up LPG tanks for short term use, anything to keep the domestic supply live.

[Ian]

Thank you Gnole for the backup on the reluctance to shut down domestic gas supplies.

Can you confirm from your direct experience that businesses can be shut off immediately without warning? as I have a couple of friends who scream "but they would be sued if they did that"

Brambles, I assume your water cylinder has a thermostat and you have a time-clock to control water heating so there must be a solenoid to control the gas therefore no electric = no hot water.

A simple old UPS or a cheapy small inverter and car batter you can plug your boiler into would solve that problem. If you want the central heating to run the UPS or inverter must be man enough to run the pump as I am sure you realise. Unfortunately that costs more.

P.S. My UPS was a chuck out from a company that was upgrading. Nothing wrong except the batteries were old and it was more cost effective for them to upgrade the UPS to a new higher capacity model than re-battery the old one. It cost me under £15 for the new batteries from Maplins.

[Brambles]

Ian, I don't have a hot water tank, it's one of those boilers that heats the water as it's needed, so I presume it also has electrical stuff. Looks like it's a strip wash, not a shower then.
This is all stuff I know nothing about, so I'm learning all the time! Thanks.
PS whats a UPS? Can you describe in idiot speak what it is, how it works and how to use it please?

[Ian]

UPS = Uninterruptable Power Supply.

A simple box with a battery charger, a battery and an inverter in to convert the 12VDC to 230VAC.

It is designed to sit 24 hours a day keeping the battery charged and then if the power fails, automaticly switches and supplies power for a short while to whatever it supplies. It also conditions the supply so spikes and voltage swings are smoothed out. Most are only low power and can't supply for long but with intelligent use can be very helpful when the power goes, cleaning up a generator output so sensitive electronics may be used for example.

[the-gnole]

That depends on the companies contract with the gas provider in the area they are in, I know that some places have an "interuptable" contract whereas others don't, usually the ones with "interuptable supplies are big users, like million cuft per day ones and they have back up supplies such as bulk LPG storage tanks, they also pay a premium tariff so that they know in advance that they "could" be cut off in an instant, but the systems are auto change over between the two gases.

If they aren't on such a tariff with the back up they "could" be cut off but would be given adequate notice of it going to happen.

Hope that helps.